Monday
July 6, 2015

Posts by SARA


Total # Posts: 4,086

Chemistry
A flask contains 25.0 mL of diethyl ether weighth 18.74 µg (micrograms). What is the density of the diethyl ether and grams per liter?
May 1, 2015

Chemistry
In an experiment, 13g of methanol and 11 g of carbon monoxide were placed in a reaction vessel. Given the following reaction C:12.0 amu O:16.0 amu H:1.0 amu CH3OH + CO --> HC2H3O2 1 What is the theoretical yield of acetic acid? 2 If the actual yield of acetic acid is 19.1 g...
May 1, 2015

Chemistry
How can you write this formula? I'm stuck
May 1, 2015

Chemistry
A mixture containing 11.9 g of calcium fluoride and 10.3 g of sulfuric acid is heated to drive off hydrogen fluorid. Given the following reaction what is the me maximum number of grams of hydrogen fluoride that can be obtied? Ca: 40.0 amu F: 19.0 amu H: 1.0 amu S 32.0 amu CaF2...
May 1, 2015

Chemistry
Molarity What is the final volume (in Liters) of a solution prepared by diluting 25 mL of 8.25 M sodium hydroxide to a concentration of 2.40 M?
May 1, 2015

Chemistry
An organic compound consists of only carbon, hydrogen, and oxygen. Through combustion analysis, 5.671g of water and 36.933g of carbon dioxide are formed from 17.422g of sample. C:12.0 amu O: 16.0 amu H:1.0 amu In the space provided please write the empirical formula and, if ...
May 1, 2015

chemistry
Calculate the mass of oxygen gas required to occupy a volume of 6 L at a pressure of 20.9 kPa and a temperature of 37◦C.
April 30, 2015

Calculus
What is the solution to the following system of equations -2x+3y+z=5 x+5y+2z=17 To do this, I used elementary operations and isolated x to get 13y+5z=37. Is that correct so far? How would I continue?
April 30, 2015

Calculus
How would I find the equilibrant of three vectors? I am given a graph of three different vectors which meet at the point (0,0)
April 30, 2015

Calculus
If 3(a,3,2)-2(3,b,b)=(-3,1,-2) determine a and b. Describe the set spanned by the vectors. I don't know how to answer this
April 30, 2015

Solved?
I found the derivative of y=3x-1 which is y=3. Then I had the two differentiated equations equal one another: 2x+3=3 and solve for x: x=0 Then I subbed x into f(x)=x^2+3x+2 and got y=2 So the coordinate is (0,2)?
April 30, 2015

Calculus
What are the coordinates of the point on the graph of f(x)=(x+1)(x+2) at which the tangent is parallel to the line with equation 3x-y-1=0? a)(-3,2) b)(-1,0) c)(0,2) d)(1,6) To answer this, I put f(x)=(x+1)(x+2) into the form f(x)=x^2+3x+2 and found the derivative which is f&#...
April 30, 2015

Calculus
What does it mean to span in R2? I have this question: Which of the following sets if vectors span R2? a) {(1,1),(-2,-2)} b) {(1,1),(1,2)} c) {(1,2),(1/2,2)} d) {(-1,1),(1,-1)}
April 29, 2015

Calculus
Thanks! I was overthinking the question
April 29, 2015

Calculus
An airplane is heading due east with an airspeed of 220km/h when it encounters a wind from the south at 76km/h. What is the direction of the resultant velocity of the airplane The answer is E19.06°N but I don't know how
April 29, 2015

SOLVED
I made a mistake... i figured it out
April 29, 2015

calculus
For the function f(x)=x^3e^x, determine intervals of increase and decrease and the absolute minimum value of f(x) To do this I found the derivative which is f'(x)=3x^2e^x. Then I set it to zero: f'(x)=0 0=3x^2e^x How would I isolate x? And when I do, I would sub that x...
April 29, 2015

Calculus
Can you please explain how I would solve these questions? 1) Which point is 2 units from the line 12x-9y-5=0? a)(8,3) b)(7/6, -7/3) c)(14,6) d)(1,1) 2.) Which of the following sets of vectors spans R2: a) {(1,1),(-2,-2)} b) {(1,1),(1,2)} c) {(1,2),(1/2,2)} d) {(-1,1),(1,-1)}
April 29, 2015

Calculus
Susan pulls on a rope sleigh with a force of 120 N. If the rope makes an angle of 25 degrees with the horizontal, what is the force that tends to lift the sleigh? a)120.00 N b)108.76 N c)50.71 N d)84.85 N how would you know?
April 28, 2015

Help
What are some things you can skip?
April 28, 2015

Calculus
How would I find the second derivative if f(x)= √(x^3+2) using the quotient rule. I got to the step where [(12x√(x^3+2))-(9x^4/√(x^3+2))]/4(x^3+2) how would i go from that to: (3x(x^3+8))/(4(x^3+2)^3/2)
April 27, 2015

critical numbers
thanks!
April 27, 2015

critical numbers
How would I find the critical numbers of f'(x)=(x-3)^3(x+4)(x^2+1)? The answer is x=-4, x=3
April 27, 2015

English
What does Georgiana represent in "The Birthmark"? feminine perfection<----- evil and greed the rewards of hard work the price of madness
April 24, 2015

AP CHEM
The pKa of acetic acid is 4.74. What is the buffering range of this acid and its conjugate base? Explain.
April 22, 2015

Laboratory Chemistry
The activity of a stock isotope is 10,000 DPM/0.10mL. If 0.25 ml of this stock is placed in 2.50 ml of water, what is the activity in the diluted specimen? My guess is that I just multiply the 10,000 DPM by the 1/10 dilution factor. I then come up with 1,000DPM/0.10ml. Does ...
April 20, 2015

Vectors
correction, the two planes are coincident that the other intersects in line
April 19, 2015

Vectors
What is the nature of intersection of these three planes: 5x+3y-z=11 -2x-7y+10z=2 6x+21y-30z=-6 I know that the answer is two parallel planes and the other one intersecting in a line. my question is how would you know that the first equation intersects in a line? Would you use...
April 19, 2015

Vectors
Determine the vector equation of a plane that contains the line with symmetric equation (x+3)/-2=(y+1)/5=(z+2)/4 and the point P(1,3,0). For this question to find the direction vector you would use subtraction with the points (-3,-1,-2) and (1,3,0). Why would it be (1,3,0)-(-3...
April 19, 2015

Vectors
At what point does the line r=(-2,3,1)+s(2,3,-1) intersect the y-axis?
April 18, 2015

Vectors
thanks!
April 17, 2015

Vectors
What is the distance between the parallel lines having equations 2x+2y=16 and x+y=0? I'm getting 2 as my answer but the answer is supposed to be 4√2
April 17, 2015

Vectors
why does this equation 3xy +y = 0 represent two planes?
April 17, 2015

Project help please!!
but I don't know how to make it into a video/commercial :(
April 16, 2015

Project help please!!
I have to come up with a product (such as soap, face cream, shampoo, cleaning spray, etc) and make a commercial for it. and I have to make up a name for it and the stuff that's found in it. I can't think of any products, I was thinking a shampoo commercial but I don&#...
April 16, 2015

calc
If f(x) = 3x^2 − 2x, 0 ≤ x ≤ 3, evaluate the Riemann sum with n = 6, taking the sample points to be right endpoints.
April 16, 2015

socials
We're the sons of liberty justified in their treatment of the loyalists
April 15, 2015

Vectors
How would I convert cartesian equation to parametric? For example: 2x-y+3z-6=0
April 14, 2015

calc
A boat leaves a dock at 3:00 PM and travels due south at a speed of 20 km/h. Another boat has been heading due east at 15 km/h and reaches the same dock at 4:00 PM. How many minutes after 3:00 PM were the two boats closest together? (Round your answer to the nearest minute.)
April 14, 2015

Math
Some number added to -12 is 45. Add this number to 30. Multiply the answer by 3. What is the final number?
April 14, 2015

Science
What does the electron shell rotate around?
April 13, 2015

Vectors
How are these two lines coincident? 1) r=(1,7)+s(2,5) 2) x=4t+3 y=10t+12
April 12, 2015

business math
Jen purchased a condo in Naples Florida for $699,000. She put 20% down and financed the rest at 5% for 35years. What are Jens total finance charge?
April 12, 2015

algebra
Factor: X^4 y-y^5
April 11, 2015

math
an airplane is flying 120 km south and 130km west of an airport. It is flying at a height of 10 km . what is the straight line distance to the airport?
April 10, 2015

linear algebra urgent
^ each of those 3 sets are vectors
April 9, 2015

linear algebra urgent
Use the Gram-Schmidt process to transform the basis 1 1 1 , 0 1 1 , 2 4 3 for the Euclidean space R3 into an orthonormal basis for R3.
April 9, 2015

Social Studies
The revolutionary war was fought on american soil. how do you think this fact influenced the role of women in war?
April 9, 2015

linear
Let W be the subspace of R5 spanned by the vectors w1, w2, w3, w4, w5, where w1 = 2 −1 1 2 0 , w2 = 1 2 0 1 −2 , w3 = 4 3 1 4 −4 , w4 = 3 1 2 −1 1 , w5 = 2 −1 2 −2 3 . Find a basis for W ⊥.
April 9, 2015

Ib math
The marks of 2376 students in an IB exam are normally distributed with mean 49 marks and variance 225 A) if the mark is 45 estimate the number of candidates who passed the exam? B) if top 7% of students are awarded a 7, find the minimum mark required to obtain a 7? mean=49 ...
April 9, 2015

World History
Thanks
April 6, 2015

World History
could you please explain what i'm suppose to do and give me some websites i can get information from.
April 6, 2015

World History
I need help. In a brief essay, explain three ways in which the Roman Catholic Church responded to the spread of Protestantism in the sixteenth century. Describe each part of the church’s response using specific facts.
April 6, 2015

astronomy
^ and any number or combination of those can be chosen.
April 5, 2015

astronomy
Even though I do not believe the Big Bang is what created the universe(although what people clam the bing bang was would have been similar to what happened when God said "Let there be light" I still have astronomy hw. haha. I am having trouble with this question. The...
April 5, 2015

linear algebra check
Use the Gram-Schmidt process to transform the basis [1 1 1] , [0 1 1] , [2 4 3] for the Euclidean space R3 into an orthonormal basis for R3. (Enter each vector in the form [x1, x2, ...]. Enter your answers as a comma-separated list.) so i went through the process and got [1/...
April 4, 2015

calc
how did you expand the determiannt
April 2, 2015

calc
If possible, find a, b, and c so that v = [a b c] is orthogonal to both w = [1 6 1] and x = [1 −9 1]
April 2, 2015

engr
what useful product can you make using recyclable items?
April 1, 2015

AP Chemistry
A 5.0 M solution of HNO3 is titrated with 0.3 M NaOH. Identify the species that have the highest concenttrations in the solution being titrated halfway to the equivalence point. A 25.15 ml of 0.35 m HNO3 was titrated with an unknown concentration of NaOH. The endpoint was ...
March 29, 2015

math check
determine whether the given vector A in M22 belongs to the span (a1,a2,a3) where a1=[1 -1; 0 3] a2=[1 1; 0 2] a3=[2 2; -1 1] and A=[5 1; -1 9] so I set up an augmented matrix , but im not sure if I set it up correctly. I made a1 a2 and a3 into columns. 1 1 2 | 5 0 0 -1 | -1 -1...
March 28, 2015

AP Chemistry
A buffered solution was created by mixing solutions of NH4Cl and NH3 at 25 C. Which species, NH4+ or NH3, has the highest concentration in this buffered solution?. Justify your answer.
March 26, 2015

accounting
If a business is purchased by the issue of 10000 $10 8% debentures trading at $95, how much is the purchase consideration? I did 10000x95, but the answer in the key is  option D instead, 95000, not 950,000... I'm totally confused..
March 25, 2015

Math.
Half of Allan's test score plus eight equals 50. What did Allen score on his test?
March 24, 2015

math
When the equation of a line is written in general form, Describe the Slope of the line when A=0 or and B=0 ? Thanks!
March 24, 2015

math
Verify that the function satisfies the three hypotheses of Rolle's Theorem on the given interval. Then find all numbers c that satisfy the conclusion of Rolle's Theorem. (Enter your answers as a comma-separated list.) f(x) = 5 − 6x + 3x2, [0, 2] can someone ...
March 23, 2015

Vectors
How would I find the direction vector parallel to a line? For example, how is (2,1) a direction vector parallel to the line -x+2y-10=0
March 20, 2015

Vectors
determine the number of solutions, the generalized parametric solution, and explain why there are no integer solutions for the equation 2x+10y=31
March 17, 2015

Vectors
Can you please explain how to answer this? What is a solution for the following system? x-4y+z=2 and -x+4y-2z=8 a) x=4s+12, y=s, z=-10 b) x=s+4, y=3s, z=-4 c) x=2s+5, y=s, z=-12 d) x=s, y=4s, z=-12
March 17, 2015

Vectors
Multiple choice: Can you please explain how to answer this? Which point does not lie on the same plane as the points P(1,5,6), Q(-2,-3,4) and R(-1,3,2) a) S(0,4,4) b) S(4,13,8) c) S(0,-1,8) d) S(1,-3,2)
March 17, 2015

Vectors
What is the distance between the parallel lines having equations 2x+2y=16 and x+y=0 a) 16 b) 4 root 2 c) 2 d) 8 I got the answer 2. I solved for y in the 2x+2y=16 equation and got 8. that gave me point (0,8) I used the d= (ax+by+c)/root (a^2+b^2) using the equation x+y=0 and ...
March 17, 2015

Vectors
To answer this I would just sub in the x and y values right? I got a) as my answer since it equals 0. Which of the following would describe the sketch of the expression xy+2y-3x-6=0 a) the planes x=-2 and y=3 b) the planes x=3 and y=-2 c) the planes x=6 and y=2 d) the planes x...
March 17, 2015

Vectors
can you please explain how to answer this: Which of the following is not a plane a) r=(1,3,4)+s(2,-1,2)+t(1,1,1), s,t∈R b) r=(2,4,2)+s(1,-2,3)+t(3,2,2), s,t∈R c) r=(3,2,3)+s(4,-4,2)+t(-2,2,-1), s,t∈R d) r=(-2,1,4)+s(2,2,-1)+t(2,2,1), s,t∈R
March 17, 2015

Vectors
The shortest distance between a point and a line occurs at: a) infinitely many points b) one unique point c) random points d) a finite number of points
March 17, 2015

Vectors
Multiple choice. How would I answer this in a short way? what is the distance between the skew lines L1:(0,4,-3)+s(-1,1,3),seR and L2: (1,2,5)+t(-3,2,5),teR? a) 4 root 2 b) 7/2 c) root 2 d) (7 root 2)/2
March 17, 2015

Vectors
no clue how to answer it. I put each slope into the y=mx+b formula and found the b values, but i'm not sure if i'm supposed to do that
March 16, 2015

Vectors
Two lines with the slopes m1=4/3 and m2=-7/2 intersect at (3,4). Determine the equations of the two lines and check your answer by solving them
March 16, 2015

Vectors
would the answer be r-(3,2,-1)+s(1,1,1)
March 16, 2015

Vectors
Determine the vector equation of a line passing through the point P(3,2,-1) and with a direction vector perpendicular to the line r=(2,-3,4)+s(1,1,-2), seR
March 16, 2015

Calculus
Determine the slope of the tangent to the function f(x)=5e^x - 2e^(2x) at the point with x-coordinate x=1
March 16, 2015

math
How would I write the equation y=3.9657(0.9982^x) in the format of g(x)=f(x)+f(x-60)?
March 14, 2015

Calculus
Find an equation of a line tangent to y = 2sin x whose slope is a maximum value in the interval (0, 2π] I believe the equation is y=2x-4pi. How is the b-value -4pi?
March 14, 2015

Vectors
Explain why the planes 3x-6y-9z+5=0 and x+2=2y+3z never intersect
March 14, 2015

Vectors
Does the point of intersection between L1:(4,9,2)+s(1,-1,-1), seR and Ls: (2,11,4)+t(5,-3,-4), teR lie on the plane 3x-2y+3z+4=0?
March 14, 2015

math
How would I solve this equation for x? 0=3.9657(0.9982^x)ln0.9982
March 14, 2015

Calculus
How would I find the instantaneous rate of change using this formula y=3.9657(0.9982^x) and given a table of values?
March 13, 2015

Swakop High
John has $6000 to invest. He invests part of it at 5% and the rest at 8%.How much should be invested at each rate to yield 6% on the total amount?
March 13, 2015

Vectors
would it be d?
March 11, 2015

Vectors
which is not a possible type of intersection between three planes? a) intersection at a point b) three coincident planes c) intersection along a line d) intersection along a line segment I know that planes can intersect in a line but I don't know which of c and d would be ...
March 11, 2015

Math
Explain how the order of operations determines how you simplify a numeric expression. explain the rules for addition, subtraction, multiplication, division, and the use of grouping symbols.
March 10, 2015

College Algebra
John invested his savings in two investment funds. The $12,000 that he invested in Fund A returned a 3% profit. The amount that he invested in Fund B returned a 10% profit. How much did he invest in Fund B, if both funds together returned a 6% profit?
March 10, 2015

Vectors
Also, R(-9,18) lies on the line
March 9, 2015

Vectors
How would you write a vector equation for a line using parametric equations? For example: A line is defined by x=-2-t and y=4+2t,teR. a) Write a vector equation for this line using parametric equations. b) write a second vector equation different from the first
March 9, 2015

Calculus
For the question "Determine the equation of the tangent to the curve y = xtanx at the point with x-coordinate π." how is the answer -πx + y + π2 = 0?
March 9, 2015

calc
At noon, ship A is 150 km west of ship B. Ship A is sailing east at 35 km/h and ship B is sailing north at 30 km/h. How fast is the distance between the ships changing at 4:00 PM?
March 9, 2015

chemistry
Monosodium glutamate (MSG), a food-flavor enhancer, has been blamed for “Chinese Restaurant Syndrome,” the symptoms of which are headaches & chest pains. MSG has the following composition by mass: 35.51 percent C, 4.77 percent H, 37.85 percent O, 8.29 percent N, & 13...
March 6, 2015

Chemistry
Monosodium glutamate (MSG), a food-flavor enhancer, has been blamed for “Chinese Restaurant Syndrome,” the symptoms of which are headaches & chest pains. MSG has the following composition by mass: 35.51 percent C, 4.77 percent H, 37.85 percent O, 8.29 percent N, & 13...
March 6, 2015

History
the 2nd one
March 4, 2015

History
Which best describes a similarity between the outcomes of the French and American revolutions? They brought about a return to absolute monarchy in both countries. They changed the world's ideas about how nations should be ruled. Both countries embraced democracy and set up...
March 4, 2015

History
Which action by the National Assembly was inspired by Enlightenment ideals and the American Revolution? It added a Bill of Rights to the French constitution. It issued the Declaration of the Rights of Man. It set up a federal tax system based on income. It banned organized ...
March 4, 2015

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